Conventionally, there have been known a non-over resist structure and an over resist structure as the structure of a printed circuit board when a surface mount device of a BGA (Ball Grid Array) type or a LGA (Land Grid Array) type is mounted on the printed circuit board through a solder.
In the non-over resist structure, a gap is formed between a land and a resist. The solder joins the side surface of the land, and the junction between the solder and the land becomes reliable. However, it is easy to cause a destruction mode in which the land exfoliates from a substrate. On the contrary, in the over resist structure, the land is stopped by the resist, so that the land does not exfoliate from the substrate. However, a junction portion between the land and the solder is only a surface of the land, so that it is easy to cause a destruction mode in which the solder exfoliates from the surface of the land.
Therefore, there is known a printed circuit board in which the non-over resist structure and the over resist structure are mixed (e.g. see Japanese Laid-open Patent Publication No. 2001-230513 (hereinafter referred to as “Patent Document 1”), and Japanese Laid-open Patent Publication No. 2002-299807 (hereinafter referred to as “Patent Document 2”).